Depends on your budget and how low of a lo range you want. The 4-1 lo range conversion would be easiest and cheapest though.

 

Teralow may be easier, but the Lowmax for a d300 is about half the price. With a clocking ring, shifter cable, and a junkyard t-case rebuilt, arguably, they'd be about the same price.
Either way, those two options are still a grand less than the Atlas.

 

Really depends on on you, how much money you have to spend and how easy you need it to be. You don't see a lot of D300s in TJs since you have to flip them and then in most cases have leak issues to deal with. I'm actually a fan of the D300 given its size. When you start doing tummy tucks and dealing with high angles on your rear driveshaft that size can be a definite plus. There are mixed opinions on Teralow. Many people love theirs, while others have had issues. Just my opinion but I think more recent sentiment has trended much more to the positive. Atlas is great if you're prepared to spend the money and if you can make it fit with your setup. So Atlas probably best but spendy and big, Teralow probably easiest but mixed reviews and D300 probably cheapest and has size going for it, but involves work and may never stop it from leaking. You make the call.

 

My biggest concern is the reliability factor. As someone stated, with the d300 comes leaking issues. With the teralow, I've been reading of people burning up the gears. The atlas on the other hand, cost. If that's the only bad thing, I think that by searching on other forums like p4x4, I might be able to save a few bucks.

Mainly I'm looking for something to gain a better crawl ratio. With the regear, I'll be able to regain some of the loss torque from running 35s on a 4cyl for highway driving

White Jeep Club member #253

 

My biggest concern is the reliability factor. As someone stated, with the d300 comes leaking issues. With the teralow, I've been reading of people burning up the gears. The atlas on the other hand, cost. If that's the only bad thing, I think that by searching on other forums like p4x4, I might be able to save a few bucks.

Mainly I'm looking for something to gain a better crawl ratio. With the regear, I'll be able to regain some of the loss torque from running 35s on a 4cyl for highway driving

White Jeep Club member #253

Just want to make sure, but no TC is going to help on the highway. Try looking around you may even be able to find a Rubi case in local you-pull yard for cheap.

 

You might want to consider a Rubi tcase.
I put one in my 97 TJ and my 92 YJ. Works awesome!

 

find a rubi in the you-pull yards here....you're lucky as hell

White Jeep Club member #253

 

Still a spendy option, but love my Atlas...

Threw a rod on the highway about 4 or 5 years ago which twisted the counter shaft on my NV4500 and ate up a ring and pinion... The atlas is still going fine today...

As a side note, you either get a better crawl ratio and have to go into a higher gear to keep up, or you lose the crawl ratio but don't have to drop back into 4 hi between trails... You can't have both...

 

thanks for the input everyone

 

If your only issue is trying to keep up between trails then shift out of 4lo, it's ok to drive in 2hi on the sections that you don't need the gearing. I regularly shift back n fourth for whatever the trail demands.

 

in my 4.0l I had a guy build me a new np231 with all dodge Dakota gears and the dodge has a has a 6 disk planetary clutch were a tj case has a 3 disk planetary and stronger gears and a bigger chain

the dodge Dakota gears and everything fit inside the jeep tcase

 

Do you want lower gearing or are you only concerned about strength? The 231 is a pretty strong t-case, it's only real weak point is the slip yoke but a good SYE fixes that and with the right one makes it shorter than an atlas. The 231 and 35s is a pretty common set up, don't think you'll have any issues strength wise. As also stated there is a bigger chain upgrade and 6 pinion planetary gear set.

 

My biggest concern is the reliability factor.

Mainly I'm looking for something to gain a better crawl ratio.

It won't help with the crawl ratio but the JBC HD NP231 is a good option. I have been running it for five years

http://www.jbconversions.com/products/np231j/complete_shortsye.php

 

Thanks for all of the information everyone. I will take all of these options into consideration

White Jeep Club member #253

 

Also note that the D300 low range is 2.62:1, so you're not gaining anything there. A 4:1 kit is available, but not cheap. After adding up the cost of a flip kit, mount, new drive shafts, etc it gets to be a pretty pricey option.

 

True, although if you aren't in a hurry you and are patient you can find some well built D300s for a lot cheaper in the classifieds on Pirate where people are moving up to Atlases and just want the D300s gone.

 

Based on all the work you are planning on doing, I suggest you sell your jeep and buy a Rubicon. Better engine, better axles, better transmission, better Tcase, 4:1 low range, lockers, etc. Seriously, you are going to have a lot of money tied up in a rig that's hard to sell if you go forward with your build plan. I probably have $15k tied up in a 97TJ when I should have just bought a $13k rubicon.

 

Bringing this one back from the dead... iam planning to do something with the tcase in my 02 tj manuel 5speed and was wondering the best options obviously atlas is the best but maybe a little over my budget... looking for a 4 to.1 ratio or maybe lower... anyone have the teralow kit or maybe any dual stick swaps with out driveshaft mods... would really appreciate your options

 

Wow. You weren't kidding. Necromancer!

What's all this about the Atlas being big? Are you thinking of the 4 speed version? The Atlas 2 speeds I've seen all seemed to be almost identical to the D300. Am I missing something, maybe?

tjstevo, if you think you need a lower 4LO gearing, the TeraLow will not change your driveline except for internal gearing. Doesn't have anything to do with driveshafts, right? I've never had it and can't speak to quality, durability, etc. I swapped in a TJ Rubi 241, but it was easy for me since I had a 2003+ model year. Everything lined up with out issue. I'm not sure whether that kind of option for you would mean a little fab work for mounts/skids or not. An Atlas would be awesome, but it will require some work.

 

The only negative I heard about the TeraLow in the 231 was someone (and it may have been from TeraFlex) stating to avoid high RPMs.
I didn't want to have to pay that amount of attention so I went a different direction..
That said, if you can do an SYE, you can easily do the Teralow

 

2 speed Atlas not even remotely close to D300 size.

 

Yeah the actual case of a 300 is pretty narrow (like 7") I would put the Atlas more in the 231 size.

 

update

Teraflex sent me a tera low for the 2.5L NP231. It's a great unit but as most have said, avoid the high rpms. if you need the high rpms like on fire roads and such between obstacles, switch it to 4HI or even 2HI. MO2500 installed my barnes 2in drop skid and it fit perfectly. As somone else stated, the biggest course of action that I should've went with from the beginning is just investing in a 4.0 and moving away from this 2.5L. I'm almost maxed out on this thing since it is my DD (Super 30 upfront/4.88 and Super 88/4.88 on 35x12.50R15. No, I barely see speeds over 70mph and my motor is almost shot at 225K)

 

Yeah, I've only ever seen them under vehicles, never side by side, and I never thought "WOW that's big!" Not sure how all the different options compare in terms of strength and ease of working on it, except that the Atlas is supposed to be far stronger than the D300, not that I imagine it matters all that much behind a 4.0L...

 

Here is an example of size differences in a 231 (right) vs a 300 (left in red , ignore the butchered 231 in front of it, it is not relevant)

Also the rear output on the 300 is about 2" shorter than the stock one as it is an upgrade.
You can probably glean if you swapped out the 231 for a 300 you would need to lengthen the rear shaft (good) and shorten the front (not as good)

 

Wish I could find that exact picture but with an Atlas II and a D300

 

How about Atlas II vs 231 with SS SYE and extrapolate:

Closest I have found

 

That's right. Also, comparing them side by side is one thing. Actually cramming the Atlas where the 231 used to be really makes you realize how much bigger it is.

 

Well if you can find a better picture have at it.
The Atlas is bigger vertically but at least that can be dealt with clearance wise, you only have so much space between the transmission output and the pinion (especially the rear) to use without having to stretch (which I am quite aware of as you know)

 

The only leak i ever had from my flipped 4 to 1 dana 300 was from the rear hd output.
The rear output yoke nut got loose, took out the seal.
the twin stick shift rails never leaked.
8 dollars later, it was fixed.

That said, after lo max 4 to 1 gears, flipping it, and front and rear hd outputs, and twin sticks, price was getting up there. I did not pay to flip it, we re drilled the trans housing instead. Price was getting near atlas area. Atlas is a stronger option imho.
doing up a 300, one part at a time, is a budget easy option.

I think atlas is the best option, but my d300 worked good!

the Creeper t18, with a 4 to 1 d300, was a nice option!
136 to 1 in low and creeper, with a wide gear spread.
Most often i was in 4hi and creeper first.
That was my sweet spot usually.
Most of the rocks in michigan are cover in mud.
U need a little wheel speed here.

 

The only leak i ever had from my flipped 4 to 1 dana 300 was from the rear hd output.The rear output yoke nut got loose, took out the seal.
the twin stick shift rails never leaked.
8 dollars later, it was fixed.

That said, after lo max 4 to 1 gears, flipping it, and front and rear hd outputs, and twin sticks, price was getting up there. I did not pay to flip it, we re drilled the trans housing instead. Price was getting near atlas area. Atlas is a stronger option imho.
doing up a 300, one part at a time, is a budget easy option.

I think atlas is the best option, but my d300 worked good!

the Creeper t18, with a 4 to 1 d300, was a nice option!
136 to 1 in low and creeper, with a wide gear spread.
Most often i was in 4hi and creeper first.
That was my sweet spot usually.
Most of the rocks in michigan are cover in mud.
U need a little wheel speed here.

That is pretty much the conclusion came too as well. The 300 is a cheap upgrade that can be done in steps.

Side note, which HD output do you have on your 300? Was it the nut working its way out causing the leak? I have been running the novak and it has been leaking but I have been suspecting it was not torqued up enough (they don't tell you in the instructions so I did stock). It seems like 150 is about right but still got a bit and just fixed my routing for my venting as I was getting locking and may have addressed it even further.